The present invention relates generally to bicycles and, more particularly, to a bicycle seat post or handlebar suspension assembly that reduces shocks from being communicated between the bicycle frame and the rider.
The primary structural component of a conventional two-wheel bicycle is the frame. Most bicycles are defined by a frame that is typically constructed from a set of tubular members that are connected together. For many bicycles, the frame is constructed from members commonly referred to as the top tube, down tube, seat tube, seat stays and chain stays, and those members are joined together at intersections commonly referred to as the head tube, seat post, bottom bracket and rear dropout. A front wheel and a rear wheel are generally attached at forward and rearward locations, respectively, with respect to frame. A handlebar and a seat extend in an upward direction from the frame at locations that are generally between the front and rear wheels. The handlebar cooperates with a fork assembly to effectuate steering of the bicycle and the seat is oriented rearward of the handlebar and commonly supports a majority of the weight of the rider. In most configurations, the seat is generally rigidly attached to a stem tube or seat post that telescopically cooperates with a seat tube of the bicycle frame.
The increased popularity in recent years of cycling, particularly on mountains and cross-country, has made shock absorbing systems in many instances a biking necessity. Many bicycles intended for off-road use are provided with fairly aggressive and complex shock or linkage systems that accommodate vertical movement of the front wheel and/or the rear wheel with respect to the bicycle frame. Although such systems dampen energy communicated to the frame of the bicycle, such systems do little to dampen vibration between the frame and the structures that interact with the rider, such as the handlebars or the seat. Others, having recognized such a shortcoming, have attempted to adapt the motion dampening strategies associated with mounting the wheels to the frame of the bicycle to connections between the seat and handlebars and the frame. Many such configurations have drawbacks that outweigh their perceived advantages.
One approach to dampening motion between the seat and the bicycle frame has been to provide a linear spring or shock assembly that is captured by the seat tube of the bicycle frame. Still another approach has been to provide a deformable suspension linkage between fixed connections of the seat and/or handlebars and the bicycle frame. Such configurations generally have a number of moveable parts, require more complex seat post constructions and/or require extensive assembly in order to achieve the desired dampened motion between the seat and the frame.
Another approach has been to provide a dampening media that is captured by the seat tube or steer tube but does not otherwise interfere with the connection of the seat or handlebars to the underlying bicycle. Such systems are only capable of dampening vibrations associated with the seat post and do not accommodate dampening of impact shocks that can occur between the seat or handlebars and the frame as the wheels encounter more than inconsequential discontinuities along the ground surface.
Still others provide a vibrational isolation mount assembly that is disposed between fairly rigid connections of the bicycle seat or handlebars and the bicycle frame. International Publication No. WO 2009/029115 discloses one such system. Unfortunately, such systems are also not without their respective drawbacks. Although such systems provide a fairly robust connection between the bicycle seat and the seat post and the seat post and the bicycle frame, such systems include a deformable connection between the seat and seat post rigid mountings. The deformable connection provides limited but nearly infinite directional translation of the seat or handlebars relative to the frame. Although such systems isolate the seat from frame vibrations, the omni-directional instability of the vibration isolation system detracts from the ability of a rider to interact with the bicycle frame in a manner in which they are accustomed.
Therefore, there is a need for a bicycle seat post or handlebar suspension assembly that provides vibrational and impact dampening between the bicycle frame and the user interface. There is a further need for a seat post assembly that provides vibration dampening but maintains responsiveness to rider interaction with the seat and/or handlebars.